Field of the Invention
The invention concerns a medical-robotic device with a kinematic chain of movable components, wherein the kinematic chain has an end effector at its movable end, and with at least one force or torque sensor for the detection of at least one force or torque value on the kinematic chain and with a control processor that controls the kinematic chain. The invention also relates to a method for operating a medical-robotic device of this type.
Description of the Prior Art
In the field of robotic-surgical interventions, which can be performed both for diagnostic and therapeutic reasons, there is also a requirement to achieve the greatest possible accuracy. A major challenge is the compensation of movements on the part of the patient, for example respiratory or cardiac movements, which can greatly impair the accuracy of treatment or diagnosis performed with a medical-robotic device. To achieve such movement compensation, it is initially necessary to detect the movements of the patient, or the patient's anatomy or predetermined anatomical features, relevant for the planned or upcoming intervention. This can take place in real time, but it is alternatively possible for the movements to be recorded and from this recording, a model is calculated to be used as the basis for movement compensation.
A variety of technical approaches to achieve increased accuracy by the use of movement compensation have become established. One example of a product for movement compensation of this type is the “Cyberknife” made by the company Accuray. This uses an external optical tracking system with which movements are optically detected contact-free. Also known are external electromagnetic tracking systems, for example made by the manufacturers Ascension and NDI. In this case, the external trackers are attached to the exterior of the patient and then located by contact-free means over a period of time specified in advance. Here, “external” refers to components that do not belong to a medical-robotic device with which the robotic-surgical intervention is actuated. Hence, such tracking systems are embodied as additional devices with their own housing, which exchange data with the medical-robotic device.
DE 10 2013 002 818 A1 discloses a device for holding a surgical instrument that is designed to be introduced through a sheath into the body of the patient. In this case, each movement of the holder device in both the longitudinal direction and the direction of rotation has the result that the sheath or trocar sleeve moves with respect to the surrounding tissue. To compensate axial movements, a holder for the sheath is arranged on a fixed guide. This enables an axial movement transmitted from the head to the trocar sleeve to be partially or completely compensated. It is also possible for rotational movements of the robotic head to be partially or completely compensated, since the trocar sleeve fan can be rotated around its longitudinal axis by a drive unit.
DE 10 2005 054 575 B3 discloses a method for controlling a robot arm in medical applications with a which a torque acting in at least one joint is detected and controlled by a control device so as to become substantially zero.